<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=>?, initial-scale=1.0">
    <title>Document</title>
    <script src="../vue.js"></script>
</head>
<body>
    <script >
            var data1  = {a:1};
            var app    = new Vue({
                el:"#app-1",
                data: data1
            });

            //  原数据添加新属性

            data1.b = 2;
            // vue实例数据增加新属性
            app.c = 3;
            //  2 underfind 2
            console.log('app.$data.b'+ app.$data.b )
            console.log('app.b'+ app.b )
            console.log('data1.b'+ data1.b)
            //  underfind 3 underfind
            console.log('app.$data.c'+ app.$data.c)
            console.log('app.c'+ app.c)
            console.log('data1.c'+ data1.c)


            // 直接给vue 中 data加新属性，是不能同步的，需要通过set方法来加
        </script>

</body>
</html>